The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Vehicle powertrains typically include a prime mover, such as an internal combustion engine, a transmission and a coupling device that transfers drive torque from the prime mover to the transmission. The transmission multiplies the drive torque by an applied gear ratio to drive the vehicle's drivetrain. Exemplary transmissions include an automatic transmission having fixed gear ratios and a continuously variable transmission (CVT) having infinitely variable gear ratios.
The coupling device often includes a torque converter that provides a fluid coupling between an output shaft of the prime mover and an input shaft of the transmission. As the output shaft accelerates, the input shaft is induced to accelerate through the fluid coupling. Once the input shaft speed is sufficiently near to the output shaft speed, a torque converter clutch (TCC) is engaged to provide a direct drive between the output shaft and the input shaft.
In some instances, an overspeed condition can arise, wherein an uncontrolled speed flare occurs in the powertrain. Such overspeed conditions can result in damage to engine, torque converter and/or transmission components.